[sdxl k-diffusion pipeline]move sigma to device (#6757)

move sigma to device

Co-authored-by: yiyixuxu <yixu310@gmail,com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

src/diffusers/pipelines/stable_diffusion_k_diffusion/pipeline_stable_diffusion_xl_k_diffusion.py

@@ -888,10 +888,9 @@ def __call__(
             sigma_min: float = self.k_diffusion_model.sigmas[0].item()
             sigma_max: float = self.k_diffusion_model.sigmas[-1].item()
             sigmas = get_sigmas_karras(n=num_inference_steps, sigma_min=sigma_min, sigma_max=sigma_max)
-            sigmas = sigmas.to(device)
         else:
             sigmas = self.scheduler.sigmas
-        sigmas = sigmas.to(prompt_embeds.dtype)
+        sigmas = sigmas.to(dtype=prompt_embeds.dtype, device=device)
 
         # 6. Prepare latent variables
         num_channels_latents = self.unet.config.in_channels